Magnetic circular dichroism parameters have been calculated for the $N(^{1}\Sigma^{+}_{g} 2440) \rightarrow Q(^{3}\Pi_{lu}$, ${}^{3}\Pi_{o+u}$, ${}^{1}\Pi_{u}$ 2431) and $N \rightarrow V(^{1}\Sigma^{+}_{u}$ 1441) transition of the halogens, in order to account for the observed MCD $spectra.^{1}$ The experimental MCD spectra are dominated by B-terms and the calculations indicate that the expected A-term for the Q($^{1}\Pi_{u}$ 2431) transition is hidden under a B-term which arises from the magnetic field mixing of this state with the V state. This mechanism alone accounts for the Cl2 spectrum. For the cases of $Br_{2}$ and $I_{2}$, spin-orbit coupling between the appropriate component states of the configuration (2431) accounts$^{2}$ for the observed absorption intensity to $^{3}\Pi_{1u}$ and this coupling has also been used in the MCD calculations. Also a coupling scheme favored by Mulliken$^{2}$ to account for the observed absorption intensity to $^{3}\Pi_{0+u}$ found to give the beat fit for the MCD spectrum. In this model the state $^{3}\Pi_{0+g}$ (2341) is assumed to mix with the ground state.

Description:

This work was supported by a grant of the Army Research Office –- Durham. $^{1}$M. Brith, M. D, Rowe, O. Schnepp, and P. J. Stephens, to be published. $^{2}$R. S. Mulliken, J. Chem. Phys. 55., 288 (1971).Author Institution: Department of Chemistry, University of Southern California

URI:

http://hdl.handle.net/1811/16286

Other Identifiers:

1974-MG-2

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